Differences between long and short positions in forward markets

Long position holder: buyer of the contract
The long position will take the delivery of the asset and pay the seller of the asset the contract value

Short position holder: seller of the contract.
The seller is obligated to deliver the asset versus the cash value of the contract at the origination date of this transaction.

When it comes to default, both parties are at risk because typically no cash is exchanged at the beginning of the transaction. However, some transactions do require that one or both sides put up some form of collateral to protect them from the defaulted party.